Rifling machine



I YRIFLING MACHINE Filed Jan. 6, 1945 INVE NTOR a Gain/Ana ,f/vo

ATTORN EYS V Patented Aug. 14, 1945 I land, assignor to the firm Schweizerische Industrie-Gesellschaft, Neuhausen,. Swi tzerland, a corporation oifSwitze'rland I Application January 6, 1943, Serial No. 471,448

- In Germany October 4, 1941 The present invention relates to a rifiing machine for shaping theinternalsurfaces of barrels for projectile propelling, apparatus and more particularly to machines for rifling xbarrels the groove bore of which is constant or tapered.

In the rifling machines hitherto known' the movement of the cutter has been produced :by combining a rotary'movement with a translatory movement. The cutter box is fixedly secured to a drawing rod which is adapted to be moved in axial direction e. g. by hydraulic means and which rod supports a spur wheel with which it must rotate. Thisspur wheel gears with a slidable rack which is movable in a direction perpendicular to the drawing rod. The end of the said rack is guided by the walls of a slot in an adjustable rifling twist regulating arm. These known machines have the drawback that there is considerable play in the various parts which are necessary to produce the rifling grooves, impair- L2Claims. go]. sc -28.1) t p liquid which has passed through thepackingi The advantages consisting in a steplessregulating of the velocity of the translatory movement of the drawing bar afforded by the hydraulic driving mechanism are increased'by the said construction. 1 The machine according to this inVentioncan be used to produce rifling grooves of a constant or of a progressive twist. The main advantage secured by the machine according to this inven-' tion is, that the drawing bar acts exactly in the direction of the axis of the barrel to be worked. As there are.no intermediate means between drawing bar and the means producing its transing thereby the 'accuracy. The regulating arm usually extended in lateral direction or above or below the rifiing machine thereby preventing an easy handling of the barrels to be worked on the machine. This is especially the case with machines for treating guns or rifles of great length.

One object of the present invention is to provide a machine that is constructed in such a manner as to facilitate the handling of the rifle or barrel to be machined and toimprove the accuracy thereof.

This object is attained by disposing about the same axis as the barrel to be machined in a draw.- ing rod bearing a cutter head and provided with a groove corresponding exactly to the twist of the rifling grooves and by providing a guide pin which is fixedly secured to the machine and cooperates with the said groove. The drawing rod is adapted to move in longitudinal direction by hydraulic or mechanic means whereas its rotation is caused by the guide pin gliding in the groove of the rod. V

The necessary movement of the drawing bar is preferably produced by a hydraulic driving. The cylinder containing the hydraulic medium, the drawing rod and the cutter box or cutter head are therefore disposed about the same axis as the rifle or barrel to be worked.

This arrangement necessitates an accurate packing system between drawing bar and cylinlatory and rotary movement a very great ac:

curacy is obtained. The machine is smaller than those inuse.

In order that the invention may be clearly understood and readily carried into practice, I have appended hereto one sheet of drawing, illustrating the same, wherein:

Fig. l is a diagrammatic view of the hydraulic rifiing machine constructed according to this invention,

Fig. 2 is a cross-section of the drawing rod,

Fig. 3 shows a packing element, x

Fig. 4 shows in longitudinal section, one end of the cylinder with a part of the drawing rod and piston and packing system.

The rifiing machine illustrated in the drawing comprises a bed I (Figures 1 to 4) supporting a barrel 2 and a hydraulic pressure cylinder 3 arranged about the same axis as the barrel 2. In

the cylinder 3 moves a piston 4 connected to the drawing bar 5. The pressure medium is fed to the cylinder 3 by a pump 6. A valve 1 controls the direction of flow of the pressure medium. Drawing rod 5 is provided with a twisted groove 8, the twist of which corresponds to the rifling twist to be produced in the barrel 2. At the end of the cylinder 3 a packing system 9 is arranged. The openings II and I2 are the inlet and outlet openings for the pressure medium. The container of the latter bears the reference 22.

A guide pin I ii is fixedly secured to the machine bed I. Pin I0 corresponds exactlyto the cross section of groove 8. When the drawing bar is moved in axial direction the guide pin in forces the bar 5 to rotate about its own axis.

The packing system 9 shown in Figure 4 is fixedly secured to the cylinder 3. Several packing elements l4 and ii are placed in the box l3. The elements l4 and I5 have the shape shown in Figure 3. They are provided with projections entering the groove 8 and corresponding exactiv to the cross section of the said groove. Cap l8 v The cutters used in connection with the machine above described may be of any known type.

The characteristic feature above described is, that the axis of the barrel which is to be provided, with rifiing grooves and or the construction the axis of the spindle producing the movement 1 of the cutter head fall in the same line; Thereby 2,382,302 'j T l I :2. ha gunbarrel nfimg'rimmne, the combination of a drawing bar provided with a helical groove corresponding to the twist of the rifles to .be produced, a pressure fluid cylinder coaxial with the bar a piston movable in the cylinder and connected With,"the bar, the front end of said cylinder being relatively close to the end of the barrelto be entered by the drawing bar, a stationary element interposed between said cylinder 'and'the barrel in the relatively narrow space between them in engagement with the helical precision is greatly increased. The machine described may be used to provide even very'long' barrels with rifling grooves of constant or of.

progressive twist.

What I claim is: 3

. 1., Irina gun barrel rifling machine, the combination of a drawing bar provided with a helical groove corresponding to the twist of the rifies to. be, roduced, meanson saidbar and coaxial therewith for imparting axial movement thereto,

groove of the drawing bar and adapted to impart rotary movement to the drawing bar while it is beingaxially moved; a packing member for the drawing bar supported by the cylinder, chambers between the packing member and the stationary element adapted to receive hydraulic pressure fluid which passed through the packing member, and a conduit for carrying off said last mentionedpressure fluid. v I

' GO'I'II-IARD-END. 

